Thyroid Eye Disease: Pilot Study Comparison Between Patients in United States-Based and India-Based Practices

PurposeThyroid eye disease (TED) phenotype varies by ethnicity/race and genetic/environmental factors. This study compared demographic and clinical characteristics of TED patients from the US and India.DesignObservational pilot studyMethods64 patients with TED ages ≥18 years old with active disease (onset of symptoms ≤18 months or presenting clinical activity score (CAS) ≥4) were recruited between March and October 2021 from clinical practices in the United States (Philadelphia, PA) (n= 30) and India (Hyderabad, India) (n=34). Data collection at baseline and 3 months included clinical measurements, thyroid disease history, and photographs. Ocular symptoms and quality of life data were obtained by phone interview. CAS was calculated using the standard 7-point scale.ResultsThere was no statistically significant difference in age, TED duration, or smoking status between patient groups. Both groups had good vision, a low rate of optic neuropathy, and comparable exophthalmometry. US patients were predominantly female (86.7% (26/30)), with a history of hyperthyroidism (96% 29/30). In comparison, Indian patients were 52.9% (18/34, p=0.004) female; underlying thyroid disease was distributed between hyperthyroidism (52%), hypothyroidism (17.6%) and euthyroid (9.7%). Mean (SD) CAS in the US cohort was double the score in the India cohort (4.2 (1.7) vs 1.65 (1.7), respectively) (P <0.0001). However, patients at both sites experienced subjective symptoms of TED at a similar frequency.ConclusionsObserved differences in TED between US and Indian patients warrant further investigation to elucidate differences in pathogenesis, disease expression, or other factors that may influence TED in diverse populations.